Alterations in
iron metabolism or oxidative damage in response to hypoxic incidents have been examined following re-oxygenation of the hypoxic tissue. To understand the consequences of decreased tissue
oxygen on
iron load,
metal-catalyzed redox activity and oxidative modifications in isolation from re-oxygenation, the present study exposed mice to either normoxia, or mild
hypoxia (380 Torr; approximately 10% normobaric
oxygen) where the tissue was not allowed to re-oxygenate prior to examination. Brain, liver and skeletal muscle were examined for Fe3+ load,
metal-catalyzed redox activity and oxidative modifications to
proteins (
N(epsilon)-(carboxymethyl)lysine),
lipids (4-hydroxynonenal pyrrole) and
nucleic acids (8-hydroxyguanosine).
Hypoxia induced a 43% increase in the
iron content of the liver (P < 0.001) as determined by ICP-MS and a 3.8-fold increase in Fe3+ load (P < 0.001) as determined by Perl's
stain. There was a corresponding 2-fold increase in
metal-catalyzed redox activity (P < 0.01) in the liver, but no change in the expression of oxidative markers. In contrast, non-significant increases in Fe3+ and
metal-catalyzed redox activity were observed in the cerebral cortex, and molecular and granular layers of the hippocampus and cerebellum. Interestingly,
hypoxia significantly decreased oxidative modifications to
proteins and
lipids, but not
nucleic acids in most brain regions examined. In addition,
hypoxia did not alter the Fe content of skeletal muscle, or the contents of Zn, Cu, Ni or Mn in liver, skeletal muscle, cerebral cortex or hippocampus. Together, these results indicate that there is a tighter regulation of
iron metabolism in the brain than the liver, which limits the redistribution of Fe3+ following
hypoxia.